Comparison of paediatric patients evaluated for postural orthostatic tachycardia syndrome with and without tachycardia.

INTRODUCTION: Postural orthostatic tachycardia syndrome is a debilitating disorder. We compared paediatric patients with this dysautonomia presenting with and without peak upright heart rate > 100 beats per minute. MATERIALS AND METHODS: Subjects were drawn from the Postural Orthostatic Tachycardia Syndrome Program database of the Children's Hospital of Philadelphia diagnosed between 2007 and 2018. Subjects were aged 12-18 years at diagnosis with demographic data, supine and peak heart rate from 10-minute stand, symptoms, and family history. Patients were divided into "low heart rate" (peak less than 100 beats/minute) and "high heart rate" (peak at least 100 beats/minute) groups. RESULTS: In total, 729 subjects were included (low heart rate group: 131 patients, high heart rate group: 598 patients). The low heart rate group had later age at diagnosis (16.1 versus 15.7, p = 0.0027). Median heart rate increase was 32 beats/minute in the low heart rate group versus 40 beats/minute in the high heart rate group (p < 0.00001). Excluding palpitations and tachypalpitations, there were no differences in symptom type or frequency between groups. DISCUSSION: Paediatric patients meeting heart rate criteria for postural orthostatic tachycardia syndrome but without peak heart rate > 100 demonstrate no difference in symptom type or frequency versus those who meet both criteria. Differences observed reached statistical significance due to population size but are not clinically meaningful. This suggests that increased heart rate, but not necessarily tachycardia, is seen in these patients, supporting previous findings suggesting maximal heart rate is not a major determinant of symptom prevalence in paediatric postural orthostatic tachycardia syndrome.

Long-Term POTS Outcomes Survey: Diagnosis, Therapy, and Clinical Outcomes.

BACKGROUND: Limited data exist on long-term outcomes in individuals with postural orthostatic tachycardia syndrome (POTS). We designed an electronic questionnaire assessing various aspects of outcomes among patients diagnosed and treated in a single-center pediatric POTS clinical program. METHODS AND RESULTS: The LT-POTS (Long Term POTS Outcomes Survey) included questions about quality of life, symptoms, therapies, education, employment, and social impact of disease. Patients age≤18 years at POTS diagnosis who were managed in the Children's Hospital of Philadelphia POTS Program were included. A total of 227 patients with POTS responded with sufficient data for interpretation. The mean age of respondents was 21.8±3.5 years. The median age of symptom onset was 13 (interquartile range 11-14) years, with mean 9.6±3.4 years symptom duration. Multiple cardiovascular, neurologic, and gastrointestinal symptoms were reported. Symptom prevalence and severity were worse for female patients, with 99% of patients reporting ongoing symptoms. Quality of life showed moderate function and limitation, with more severe limitations in energy/fatigue and general health. Nearly three quarters of patients had diagnostic delays, and over half were told that their symptoms were "in their head." Multiple medications were used and were felt to be effective, whereas fewer nonpharmacologic interventions demonstrated efficacy. Nearly 90% of patients required continued nonpharmacologic therapy to control symptoms. CONCLUSIONS: POTS is a chronic disorder leading to significant disability with a range of multisystem problems. Although symptoms can be modifiable, it rarely spontaneously resolves. Improved understanding of POTS presentation and therapeutic approaches may inform provider education, improve diagnostic success, and help patients self-advocate for appropriate medical management approaches.

Assessment of comorbid symptoms in pediatric autonomic dysfunction.

PURPOSE: Pediatric patients with autonomic dysfunction and orthostatic intolerance (OI) often present with co-existing symptoms and signs that might or might not directly relate to the autonomic nervous system. Our objective was to identify validated screening instruments to characterize these comorbidities and their impact on youth functioning. METHODS: The Pediatric Assembly of the American Autonomic Society reviewed the current state of practice for identifying symptom comorbidities in youth with OI. The assembly includes physicians, physician-scientists, scientists, advanced practice providers, psychologists, and a statistician with expertise in pediatric disorders of OI. A total of 26 representatives from the various specialties engaged in iterative meetings to: (1) identify and then develop consensus on the symptoms to be assessed, (2) establish committees to review the literature for screening measures by member expertise, and (3) delineate the specific criteria for systematically evaluating the measures and for making measure recommendations by symptom domains. RESULTS: We review the measures evaluated and recommend one measure per system/concern so that assessment results from unrelated clinical centers are comparable. We have created a repository to apprise investigators of validated, vetted assessment tools to enhance comparisons across cohorts of youth with autonomic dysfunction and OI. CONCLUSION: This effort can facilitate collaboration among clinical settings to advance the science and clinical treatment of these youth. This effort is essential to improving management of these vulnerable patients as well as to comparing research findings from different centers.

Emergency Department utilisation and diagnoses in adolescents with postural orthostatic tachycardia syndrome.

INTRODUCTION: Data for Emergency Department utilisation and diagnoses in adolescents with postural orthostatic tachycardia syndrome are lacking, making prevention of these visits more difficult to achieve. MATERIALS AND METHODS: We performed a retrospective study of patients with postural orthostatic tachycardia syndrome between ages 12 and 18 years seen in the Emergency Department at a large tertiary care children's hospital. These subjects were age- and sex-matched with controls, with volume of primary and total diagnoses assessed. Due to the relatively small number of subjects, a ± 3-year variance was used among control patients for age matching. RESULTS: A total of 297 patients in each group were evaluated. The percentage of female patients was 80.5%. The median age of the subjects was 15.1 years (interquartile range 14.1-15.9), and the median age of controls was 16.1 years (interquartile range 14.4-17.4) (p < 0.00001). Patients with postural orthostatic tachycardia syndrome had greater gastroenterologic and headache diagnoses (p < 0.00001); controls had greater autonomic and psychiatric diagnoses. DISCUSSION: Adolescent patients with postural orthostatic tachycardia syndrome who present to the Emergency Department have a preponderance of gastroenterologic and headache complaints versus controls.

Creating a data dictionary for pediatric autonomic disorders.

PURPOSE: Whether evaluating patients clinically, documenting care in the electronic health record, performing research, or communicating with administrative agencies, the use of a common set of terms and definitions is vital to ensure appropriate use of language. At a 2017 meeting of the Pediatric Section of the American Autonomic Society, it was determined that an autonomic data dictionary comprising aspects of evaluation and management of pediatric patients with autonomic disorders would be an important resource for multiple stakeholders. METHODS: Our group created the list of terms for the dictionary. Definitions were prioritized to be obtained from established sources with which to harmonize. Some definitions needed mild modification from original sources. The next tier of sources included published consensus statements, followed by Internet sources. In the absence of appropriate sources, we created a definition. RESULTS: A total of 589 terms were listed and defined in the dictionary. Terms were organized by Signs/Symptoms, Triggers, Co-morbid Disorders, Family History, Medications, Medical Devices, Physical Examination Findings, Testing, and Diagnoses. CONCLUSION: Creation of this data dictionary becomes the foundation of future clinical care and investigative research in pediatric autonomic disorders, and can be used as a building block for a subsequent adult autonomic data dictionary.

Pediatric Postural Orthostatic Tachycardia Syndrome: Where We Stand.

Postural orthostatic tachycardia syndrome (POTS), first described in 1992, remains an enigmatic, yet severely and variably debilitating, disorder. The pathophysiology of this syndrome is still not understood, and there remains no biomarker indicating the presence of POTS. Although research interest has increased in recent years, there are relatively fewer clinical and research studies addressing POTS in children and adolescents compared with adults. Yet, adolescence is when a large number of cases of POTS begin, even among adult patients who are subsequently studied. This article summarizes reported research in POTS, specifically in pediatric patients, including discussion of aspects of diagnostic criteria, risk factors and outcomes, neurohormonal and hemodynamic abnormalities, clinical assessment, and treatment. The goals of this review are increased recognition and acknowledgment of POTS among pediatric and adolescent providers, as well as to provide an understanding of reported abnormalities of homeostasis, such that symptomatic patients will be able to be recognized and appropriately managed, enabling them to return to their activities of daily living.

Postural orthostatic tachycardia syndrome (POTS): Priorities for POTS care and research from a 2019 National Institutes of Health Expert Consensus Meeting - Part 2.

The National Institutes of Health hosted a workshop in 2019 to build consensus around the current state of understanding of the pathophysiology of postural orthostatic tachycardia syndrome (POTS) and to identify knowledge gaps that must be addressed to enhance clinical care of POTS patients through research. This second (of two) articles summarizes current knowledge gaps, and outlines the clinical and research priorities for POTS. POTS is a complex, multi-system, chronic disorder of the autonomic nervous system characterized by orthostatic intolerance and orthostatic tachycardia without hypotension. Patients often experience a host of other related disabling symptoms. The functional and economic impacts of this disorder are significant. The pathophysiology remains incompletely understood. Beyond the significant gaps in understanding the disorder itself, there is a paucity of evidence to guide treatment which can contribute to suboptimal care for this patient population. The vast majority of physicians have minimal to no familiarity or training in the assessment and management of POTS. Funding for POTS research remains very low relative to the size of the patient population and impact of the syndrome. In addition to efforts to improve awareness and physician education, an investment in research infrastructure including the development of standardized disease-specific evaluation tools and outcome measures is needed to facilitate effective collaborative research. A national POTS research consortium could facilitate well-controlled multidisciplinary clinical research studies and therapeutic trials. These priorities will require a substantial increase in the number of research investigators and the amount of research funding in this area.

Nomenclature for Pediatric and Congenital Cardiac Care: Unification of Clinical and Administrative Nomenclature - The 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11).

Substantial progress has been made in the standardization of nomenclature for paediatric and congenital cardiac care. In 1936, Maude Abbott published her Atlas of Congenital Cardiac Disease, which was the first formal attempt to classify congenital heart disease. The International Paediatric and Congenital Cardiac Code (IPCCC) is now utilized worldwide and has most recently become the paediatric and congenital cardiac component of the Eleventh Revision of the International Classification of Diseases (ICD-11). The most recent publication of the IPCCC was in 2017. This manuscript provides an updated 2021 version of the IPCCC.The International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD), in collaboration with the World Health Organization (WHO), developed the paediatric and congenital cardiac nomenclature that is now within the eleventh version of the International Classification of Diseases (ICD-11). This unification of IPCCC and ICD-11 is the IPCCC ICD-11 Nomenclature and is the first time that the clinical nomenclature for paediatric and congenital cardiac care and the administrative nomenclature for paediatric and congenital cardiac care are harmonized. The resultant congenital cardiac component of ICD-11 was increased from 29 congenital cardiac codes in ICD-9 and 73 congenital cardiac codes in ICD-10 to 318 codes submitted by ISNPCHD through 2018 for incorporation into ICD-11. After these 318 terms were incorporated into ICD-11 in 2018, the WHO ICD-11 team added an additional 49 terms, some of which are acceptable legacy terms from ICD-10, while others provide greater granularity than the ISNPCHD thought was originally acceptable. Thus, the total number of paediatric and congenital cardiac terms in ICD-11 is 367. In this manuscript, we describe and review the terminology, hierarchy, and definitions of the IPCCC ICD-11 Nomenclature. This article, therefore, presents a global system of nomenclature for paediatric and congenital cardiac care that unifies clinical and administrative nomenclature.The members of ISNPCHD realize that the nomenclature published in this manuscript will continue to evolve. The version of the IPCCC that was published in 2017 has evolved and changed, and it is now replaced by this 2021 version. In the future, ISNPCHD will again publish updated versions of IPCCC, as IPCCC continues to evolve.

Nomenclature for Pediatric and Congenital Cardiac Care: Unification of Clinical and Administrative Nomenclature - The 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11).

Substantial progress has been made in the standardization of nomenclature for paediatric and congenital cardiac care. In 1936, Maude Abbott published her Atlas of Congenital Cardiac Disease, which was the first formal attempt to classify congenital heart disease. The International Paediatric and Congenital Cardiac Code (IPCCC) is now utilized worldwide and has most recently become the paediatric and congenital cardiac component of the Eleventh Revision of the International Classification of Diseases (ICD-11). The most recent publication of the IPCCC was in 2017. This manuscript provides an updated 2021 version of the IPCCC.The International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD), in collaboration with the World Health Organization (WHO), developed the paediatric and congenital cardiac nomenclature that is now within the eleventh version of the International Classification of Diseases (ICD-11). This unification of IPCCC and ICD-11 is the IPCCC ICD-11 Nomenclature and is the first time that the clinical nomenclature for paediatric and congenital cardiac care and the administrative nomenclature for paediatric and congenital cardiac care are harmonized. The resultant congenital cardiac component of ICD-11 was increased from 29 congenital cardiac codes in ICD-9 and 73 congenital cardiac codes in ICD-10 to 318 codes submitted by ISNPCHD through 2018 for incorporation into ICD-11. After these 318 terms were incorporated into ICD-11 in 2018, the WHO ICD-11 team added an additional 49 terms, some of which are acceptable legacy terms from ICD-10, while others provide greater granularity than the ISNPCHD thought was originally acceptable. Thus, the total number of paediatric and congenital cardiac terms in ICD-11 is 367. In this manuscript, we describe and review the terminology, hierarchy, and definitions of the IPCCC ICD-11 Nomenclature. This article, therefore, presents a global system of nomenclature for paediatric and congenital cardiac care that unifies clinical and administrative nomenclature.The members of ISNPCHD realize that the nomenclature published in this manuscript will continue to evolve. The version of the IPCCC that was published in 2017 has evolved and changed, and it is now replaced by this 2021 version. In the future, ISNPCHD will again publish updated versions of IPCCC, as IPCCC continues to evolve.

Postural orthostatic tachycardia syndrome (POTS): State of the science and clinical care from a 2019 National Institutes of Health Expert Consensus Meeting - Part 1.

Postural orthostatic tachycardia syndrome (POTS) is a chronic and often disabling disorder characterized by orthostatic intolerance with excessive heart rate increase without hypotension during upright posture. Patients often experience a constellation of other typical symptoms including fatigue, exercise intolerance and gastrointestinal distress. A typical patient with POTS is a female of child-bearing age, who often first displays symptoms in adolescence. The onset of POTS may be precipitated by immunological stressors such as a viral infection. A variety of pathophysiologies are involved in the abnormal postural tachycardia response; however, the pathophysiology of the syndrome is incompletely understood and undoubtedly multifaceted. Clinicians and researchers focused on POTS convened at the National Institutes of Health in July 2019 to discuss the current state of understanding of the pathophysiology of POTS and to identify priorities for POTS research. This article, the first of two articles summarizing the information discussed at this meeting, summarizes the current understanding of this disorder and best practices for clinical care. The evaluation of a patient with suspected POTS should seek to establish the diagnosis, identify co-morbid conditions, and exclude conditions that could cause or mimic the syndrome. Once diagnosed, management typically begins with patient education and non-pharmacologic treatment options. Various medications are often used to address specific symptoms, but there are currently no FDA-approved medications for the treatment of POTS, and evidence for many of the medications used to treat POTS is not robust.

Prevalence of joint hypermobility syndromes in pediatric postural orthostatic tachycardia syndrome.

INTRODUCTION: Patients with postural orthostatic tachycardia syndrome (POTS) have been shown to exhibit comorbid joint hypermobility manifested as Ehlers-Danlos syndrome (EDS) or hypermobility spectrum disorder (HSD). The prevalence of EDS and HSD in POTS has been demonstrated in smaller studies combining adult and pediatric patients. We examined a large series of pediatric patients to determine their prevalence in children with POTS. MATERIALS AND METHODS: Patients 18 years old, or less, at initial evaluation at our clinic were included. POTS was diagnosed based on at least six months of frequent debilitating symptoms of orthostatic intolerance, plus a consistent heart rate increase of at least 40 beats per minute without orthostatic hypotension on standing test. Patients with a Beighton score of at least 5/9 plus other systemic findings suggestive of EDS were further evaluated in Connective Tissue Disorders clinics. RESULTS: There were 362 patients meeting inclusion criteria, of which 82 patients had EDS (22.7%) and 141 patients had HSD (39.0%). Patients with EDS had an earlier median age at symptom onset (12.1 vs. 13.5 years, p=0.004) and longer median symptom duration (2.5 vs. 1.5 years, p=0.0008) compared to patients without hypermobility. CONCLUSIONS: Our evaluation of a large series of pediatric patients with POTS revealed that over one-fifth of patients had EDS and over one-third of patients had HSD. The awareness of the prevalence of comorbidities such as hypermobility disorders may help inform providers diagnosing and caring for these patients.

Family history of associated disorders in patients with postural tachycardia syndrome.

INTRODUCTION: Postural tachycardia syndrome is more frequently being recognised in adolescents and adults. However, its pathophysiology remains undefined. We evaluated our database for patterns in family history of clinical symptoms and associated disorders in these patients. MATERIALS AND METHODS: Patients with postural tachycardia syndrome diagnosed in our clinic between 2014 and 2018 and who were less than 19 years at diagnosis were included. The history was reviewed for family members with postural tachycardia syndrome, dizziness and/or syncope, joint hypermobility with or without hypermobile Ehlers-Danlos syndrome, and autoimmune disorders. Statistical analysis assessed the entire cohort plus differences in gender, presence or absence of joint hypermobility, and presence or absence of familial autoimmune disease. RESULTS: A total of 579 patients met inclusion criteria. We found that 14.2% of patients had a family member with postural tachycardia syndrome, with male patients more likely to have an affected family member (20% versus 12.7%, p = 0.04). If the patient also had joint hypermobility, male patients were more likely to have a family member with postural tachycardia syndrome (25% versus 12.6%, p = 0.017), more than one affected family member (7.1% versus 0.74%, p = 0.001), and a family member with joint hypermobility (37.5% versus 23.7%, p = 0.032). Autoimmune disease was seen in 45.1% of family members, but more likely in female patients with concurrent hypermobility (21.1% versus 8.9%, p = 0.035). DISCUSSION: This in-depth analysis of associated familial disorders in patients with postural tachycardia syndrome offers further insight into the pathophysiology of the disorder, and informs further screening of family members in these patients.

Orthostatic heart rate does not predict symptomatic burden in pediatric patients with chronic orthostatic intolerance.

PURPOSE: Postural orthostatic tachycardia syndrome (POTS) in adults is defined as symptoms of chronic orthostatic intolerance (COI) and autonomic dysfunction (AD) with heart rate (HR) increase of 30 beats per minute (bpm), or HR > 120 bpm, during prolonged upright position. However, in adolescents, POTS is defined as symptoms of OI and AD with HR increase of ≥ 40 bpm, based on tilt table data. We assessed frequency of COI symptoms in pediatric patients versus HR criteria on prolonged standing to evaluate using criteria of increased HR of 30-39 bpm versus ≥ 40 bpm in our POTS Program. METHODS: Patients with COI with symptoms for > 3 months plus HR increase of ≥ 30 bpm on 10 min stand aged ≤ 18 years at diagnosis were included. Patients were divided into two groups: those with HR increase of 30-39 bpm, and those with HR increase of ≥ 40 bpm or upright HR of > 120 bpm. A total of 28 symptoms described prior to diagnosis were evaluated using chi-square testing to assess for significant differences. RESULTS: Only insomnia was found to be significantly different between the two groups. The other 27 symptoms showed no significant difference as a function of HR. CONCLUSION: There are minimal statistically significant differences and no clinical differences between patients as a function of HR increase during standing. Thus, a 40-bpm threshold for adolescents on standing test may be too high, or a specific HR criteria threshold is neither predictive nor definitive in diagnosing POTS.

Clinical Course of Transgender Adolescents with Complicated Postural Orthostatic Tachycardia Syndrome Undergoing Hormonal Therapy in Gender Transition: A Case Series.

Purpose: Postural orthostatic tachycardia syndrome (POTS), an increasingly recognized dysautonomia, may affect as many as 3,000,000 Americans. Concurrently, prevalence estimates suggest 10% of individuals identify as lesbian, gay, bisexual, transgender, or questioning/queer. The preponderance of female POTS patients implies hormonal differences between natal sexes and their role in POTS. Transgender POTS patients using hormone therapies may offer further insight into the mechanism of POTS. There have been no previously published studies of transgender patients with POTS undergoing gender-affirming hormone therapy. Methods: We reviewed our electronic health record for clinical histories of transgender patients in our POTS Database. Results: Three patients who transitioned from female to male demonstrated clinical improvement of their POTS symptoms with the addition of testosterone therapy. Conclusion: We present our clinical experience of three transgender POTS patients who transitioned from female to male with hormone therapy, all of whom demonstrated clinical improvement with testosterone. This may give further insight into the pathophysiology of POTS. However, the authors do not endorse the use of hormone therapy as primary therapy for the symptoms of POTS.

Therapy for fatigue and cognitive dysfunction in postural orthostatic tachycardia syndrome.

IntroductionSevere fatigue and cognitive dysfunction are frequent symptoms in patients with postural orthostatic tachycardia syndrome. They can be debilitating, and often do not resolve despite improvement in haemodynamic symptoms. Our analysis was intended to assess clinical outcomes of medication treatment for these symptoms in a large, single-centre paediatric programme.Materials and MethodsWe performed a retrospective review of patients treated for fatigue and cognitive dysfunction. Patients aged 18 years or younger at the time of initial diagnosis were included. Patients who had a specific medication ordered five or more times for these symptoms were confirmed by chart review for clinical improvement. Percentage of patients with clinical improvement for each medication and overall for all medications, as well as the number of medications per patient required to achieve improvement, were assessed. Data were analysed based on gender as well. t-Test and χ2 analyses were used to assess for differences between means in variables, or specific variables. RESULTS: A total of 708 patients met study criteria, of whom 517 were treated for fatigue or brain fog. Overall efficacy was 68.8%, with individual medication effectiveness ranging from 53.1 (methylphenidate) to 16.5% (atomoxetine). There was no significant difference in efficacy with respect to gender. The median number of medications used per patient was 2, without gender difference. Therapy was limited by side effects or lack of efficacy.DiscussionMedications are effective in the improvement of fatigue and cognitive dysfunction in these patients. However, trials of multiple medications may be needed before achieving clinical improvement.

Utilisation of medications to reduce symptoms in children with postural orthostatic tachycardia syndrome.

BACKGROUND: Postural orthostatic tachycardia syndrome encompasses multiple disabling symptoms that interfere with daily activities. Non-pharmacologic approaches can be insufficient and can require adjunctive medications to manage symptoms. Minimal data exist in the literature on medication outcomes in these patients. We reviewed our database for medication management outcomes.Materials and MethodsPatients aged 18 years and younger at initial diagnosis met the inclusion criteria. All prescribed patient medications were extracted from the electronic health record, excluding medications for unrelated symptoms or comorbid diseases. Medications were grouped by symptom class consistent with our programme utilisation protocol. Within symptom classification, therapy was deemed successful when a specific dose was prescribed at least five consecutive times without changes; this was confirmed by chart review. Individual medications and overall percentage of successful therapies within symptom classifications were assessed, with further analysis by gender. t-Test, χ2, and Mann-Whitney U-test were used to assess for differences in specific variables, as appropriate. RESULTS: A total of 708 patients met the study criteria. The percentage of patients with effective therapy by symptom includes light-headedness (52.2%), headache (48.2%), nausea (39.1%), dysmotility (43.4%), pain (53.4%), and insomnia (42.8%). Insomnia therapy was better for females; all other therapies showed no gender difference. The median number of therapies prescribed per patient per symptom was 2 for light-headedness, headache, and insomnia, and 1 for nausea, dysmotility, and pain.DiscussionSymptoms associated with this disorder can be effectively managed with various medications. Further randomised studies are needed to better ascertain true efficacy compared with placebo.

Classification of Ventricular Septal Defects for the Eleventh Iteration of the International Classification of Diseases-Striving for Consensus: A Report From the International Society for Nomenclature of Paediatric and Congenital Heart Disease.

The definition and classification of ventricular septal defects have been fraught with controversy. The International Society for Nomenclature of Paediatric and Congenital Heart Disease is a group of international specialists in pediatric cardiology, cardiac surgery, cardiac morphology, and cardiac pathology that has met annually for the past 9 years in an effort to unify by consensus the divergent approaches to describe ventricular septal defects. These efforts have culminated in acceptance of the classification system by the World Health Organization into the 11th Iteration of the International Classification of Diseases. The scheme to categorize a ventricular septal defect uses both its location and the structures along its borders, thereby bridging the two most popular and disparate classification approaches and providing a common language for describing each phenotype. Although the first-order terms are based on the geographic categories of central perimembranous, inlet, trabecular muscular, and outlet defects, inlet and outlet defects are further characterized by descriptors that incorporate the borders of the defect, namely the perimembranous, muscular, and juxta-arterial types. The Society recognizes that it is equally valid to classify these defects by geography or borders, so the emphasis in this system is on the second-order terms that incorporate both geography and borders to describe each phenotype. The unified terminology should help the medical community describe with better precision all types of ventricular septal defects.